Hey Trent,
As for the letter....I received it like 2 weeks ago, had interview March 28th, and the letter read the following...After successfully completing the interview process you are now officially on the "ranked waitlist" for USC,...and it goes on to say that they can't really tell you where you stand on the list but that my application will be under review until first day of classes. Probably not a letter of great importance because I'm sure a lot of people got it, but we will see what happens. Did you get any letter at all after your interview?